Despite the recognition of obvious breast cancer (BC) racial-health disparity, we have failed to reduce the BC outcome gaps in African American women. Unavailability of three-dimensional (3D) tissue culture model systems that mimics the original tumor?s architecture and molecular characteristics of the racially disparate breast tumors limits our advancement in this area. The overall goal of this SBIR Phase-I proposal is to develop a standardized protocol for the establishment of a three-dimensional (3D) tissue culture model system using tumor mass from breast cancer patients of African American and Caucasian American racial/ethnic background. We will achieve overall goal in three parts: ?A? development of 3D-tissue culture model system from racially disparate breast tumors; ?B? phenotypic characterization of the developed 3D model system to confirm their stability and; ?C? functional characterization and technical validation of the developed 3D-tissue culture models. Successful completion of this highly innovative proposal will result in a novel phenotypically stable 3D-culture model system that will be a landmark in BC racial disparity research. Moreover, this will provide a strong foundation for our next step, in that we will pursue a Phase II for developing up to 50 3D-tissue culture model system for racially disparate BC of different molecular subtypes.